Process for forming synthetic fiber and fiber, yarns and carpets produced thereby

ABSTRACT

Processes for forming synthetic fibers from polymer melts containing a first fiber forming polymer, a spin assist additive, and optionally a pigment additive are provided. Also provided are synthetic fibers of a first fiber forming polymer, a spin assist additive, and optionally a pigment additive, as well as articles of manufacture such as yarns, carpets and fabrics made up of these synthetic fibers.

FIELD OF INVENTION

The present disclosure relates to extrusion and spinning processes forforming synthetic fibers from polymer melts comprising a first fiberforming polymer, a spin assist additive, and an optional pigmentedadditive. The present disclosure also relates to synthetic fiberscomprising a first fiber forming polymer, a spin assist additive, andoptionally a pigmented additive, as well as articles of manufacture suchas yarns, carpets and fabrics comprising these synthetic fibers.

BACKGROUND

Use of solution dyed nylon (SDN) fibers as a replacement for white yarnsis increasing in both residential and commercial textile markets. Oneproblem that continues to hamper the broader use of SDN fibers is therelative difficulty in spinning fiber from SDN polymer, due to increasednucleation caused by the pigments used to color the spun fiber. SDNyarns are more difficult to draw, and this outcome produces poor yieldsfor many pigmented SDN fibers. This problem is more severe when usinghard to spin pigments, examples of which include, but are not limitedto, Pigment Green 70, Pigment Red 81, and Pigment Red 67, and whilespinning yarns with high loading of organic pigments.

To mitigate this problem, nylon copolymers made from monomers such asMPMD, isophthalic acid (I) and 5-sulfoisophthalic acid (SIPA) have beenused. See U.S. Pat. No. 5,422,420, U.S. Pat. No. 5,290,850 and U.S. Pat.No. 5,223,196.

In addition, U.S. Pat. No. 3,926,924 discloses a ternary fiber-formingcopolyamide for use in apparel fabrics consisting of at last 50% byweight hexamethylene adipamide, 20-40 percent by weight hexamethyleneterephthalamide and 2-20 percent by weight of a third polyamide such aspolyepsilon caprolactam (nylon 6), polyhexamethylene isophthalamide(nylon 6I), polyhexamethylene sebacamide (nylon 6,10), polyhexamethylenesuberamide (nylon 6,8) or poly(a-amino undecanoic acid) (nylon 11).

U.S. Pat. No. 4,238,603 discloses fiber-forming polymers prepared from amixture of the hexamethylene diamine salts of terephthalic acid,isophthalic acids, and a smaller amount of at least one aliphaticdibasic acid having 5 to 12 carbon atoms.

U.S. Pat. No. 5,185,428 discloses a copolyadipamide consisting ofbetween 60 and 99.5 mole percent hexamethylene adipamide units andbetween about 0.5 and 40 mole percent pentamethylene adipamide units,also referred to nylon 66/56.

U.S. Pat. No. 5,194,578 discloses a copolyamide consisting of between 60and 99.5 mole percent hexamethylene adipamide units and between about0.5 and 40 mole percent 2-methyl-pentamethylene adipamide units, alsoreferred to nylon 66/Me5-6.

Accordingly, there is a need for processes for producing SDN fibers withimproved yields which will enable improved productivity in manufacturingand lower costs of products made from such SDN fibers.

SUMMARY OF THE INVENTION

An aspect of the present invention relates to a process for forming asynthetic fiber. In this process, a polymer melt comprising a firstfiber forming polymer, a spin assist additive, and a pigment additive isproduced and a synthetic fiber is formed from the polymer melt.

In one nonlimiting embodiment, the spin assist additive is present in arange from about 0.5 to about 5 percent by weight.

In one nonlimiting embodiment, the spin assist additive is a polyamidecomprising at least one aliphatic diamine and at least two distinctaromatic dicarboxylic acids, and copolymers and blends thereof.

In one nonlimiting embodiment, the pigment additive is present in arange from about 0.01 to about 5 percent by weight.

Another aspect of the present invention relates to a synthetic fibercomprising a first fiber forming polymer, a spin assist additive and apigment additive.

In one nonlimiting embodiment, the spin assist additive is present inthe synthetic fiber at a range from about 0.5 to about 5 percent byweight.

In one nonlimiting embodiment, the spin assist additive is a polyamidecomprising at least one aliphatic diamine and at least two distinctaromatic dicarboxylic acids, and copolymers and blends thereof.

In one nonlimiting embodiment, the pigment additive is present in thesynthetic fiber at a range from about 0.01 to about 5 by weight.

Another aspect of the present invention relates to an article ofmanufacture comprising one or more synthetic fibers of the presentinvention. In one nonlimiting embodiment, the article of manufacture isa yarn formed from one or more synthetic fibers of the presentinvention. In another nonlimiting embodiment, the article of manufactureis a carpet comprising yarns formed from one or more synthetic fibers ofthe present invention. In another nonlimiting embodiment, the article ofmanufacture is a fabric formed from one or more synthetic fibers of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to polymer additives which improve thespinnability of solution dyed nylon (SDN) fibers. Accordingly, providedby the present invention are processes for production of these syntheticfibers, synthetic fibers produced comprising these polymer additives,and articles of manufacture comprising one or more of these syntheticfibers.

Abbreviations and Definitions

BF—broken filament

D—methylpentamethylene diamine

DP—differential pressure: the pressure difference measured at either endof a spin pack positioned upstream of a spinneret

I—isophthalic acid

MPMD—methylpentamethylene diamine

RV—relative viscosity, as is commonly understood in the trade and as canbe determined by ASTM D789.

SDN—solution dyed nylon

SIPA—5-sulfoisophthalic acid

Fiber—as used herein, the term fiber refers to one or more extrudedfilaments. The fibers in the disclosure may refer to staple fibers,continuous fibers, textile fibers or monofilaments.

In the processes of the present invention, a polymer melt comprising afirst fiber forming polymer and a spin assist additive is produced.

Examples of first fiber forming polymers useful in the processes of thepresent invention include, but are not limited to, polyamides,polyesters, polyolefins and combinations thereof. In one nonlimitingembodiment, the first fiber forming polymer is polyethyleneterephthalate. The polyamide may be selected from the list consisting ofnylon 6; nylon 6,6; nylon 4,6; nylon 6,12; nylon 6,10;; nylon 7; nylon11; and nylon 12; and blends and copolymers thereof. In one nonlimitingembodiment, the first fiber forming polymer is nylon 6,6.

In one nonlimiting embodiment, the first fiber forming polymer ispresent in a range from about 75 to about 99 percent by weight.

Prior disclosed use for several of the polymers found by the inventorsherein to be useful as spin assist additives was for making injectionmolded articles, and transparent nylon films. Thus, efficacy of theseadditives as spin assist additives in the production of nylon fiber isunexpected. Spin assist additives useful in the present inventioninclude polyamides comprising at least one aliphatic diamine and atleast two distinct aromatic dicarboxylic acids, and copolymers andblends thereof. Examples include, but are not limited to, polyamidescomprising at least one aliphatic diamine, and at least one aromaticdicarboxylic acid. Suitable diamines are selected from a groupconsisting of 2-methyl-1,5-pentamethylene diamine, hexamethylenediamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine,2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine,5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylenediamine and diaminodicyclohexyl methane. Suitable aromatic diacids areselected from a group consisting of terephthalic acid, isophthalic acidand naphthalene dicarboxylic acid and 5-sulfoisophthalic acid.

The spin additive may also further comprise aliphatic dicarboxylic acidsand polyamides formed from the aliphatic diamines and aliphaticdicarboxylic acids. Suitable aliphatic dicarboxylic acids include, butare not limited to succinic acid, glutaric acid, adipic acid, pimelicacid, suberic acid, azelaic acid and sebacic acid. In one nonlimitingembodiment, the aliphatic dicarboxylic acid is adipic acid.

In one nonlimiting embodiment, the spin assist additive is selected fromthe group consisting of nylon DT, nylon DI, nylon 6I, nylon 6T, nylon 6,nylon 6,6, and copolymers and blends thereof.

In one nonlimiting embodiment, the spin assist additive is a compositioncomprising a copolyamide containing about 40 to about 80 mol %2-methyl-1,5-pentamethylene terephthalamide (“DT”) repeat units, andabout 20 to about 60 mol % 2-methyl-L5-pentamethyleneisophthalamide(“DI”) repeat units. In another nonlimiting embodiment, the copolyamidehas a relative viscosity (“RV”) of at least 1.90.

In one nonlimiting embodiment, the spin assist additive is present in arange from about 0.5 to about 5 percent by weight. In anothernonlimiting embodiment, the spin assist additive is present in a rangefrom about 0.5 to about 5 percent by weight.

In some embodiments of the present invention, a pigment additive is alsoadded to the polymer melt. For purposes of the present invention, bypigment or pigment additive, it is meant to be inclusive, but is notlimited to, a color pigment of one of the three families of thetrichromatic dye color system (blues, yellows, reds) that can be addedto a polymeric fiber in an amount effective to reduce the L* value ofthe fiber over a non-color pigmented fiber. It is also meant to beinclusive of green pigments such as Green 70, also known as PigmentGreen 7. Preferable color pigments are stable in light (color fast). Asthose well versed in the art will note, the trichromatic color system iswidely practiced in the fiber dyeing industry. In this invention, thecolor pigments belong to this color system of blues, reds and yellows.In one nonlimiting embodiment, the pigment additive is an organicpigment. Nonlimiting examples of pigment additives useful in the presentinvention include, red pigments such as Pigment Red 60, Pigment Red 63,Pigment Red 80, Pigment Red 66, Pigment Red 67, Pigment Red 81, PigmentRed 68, Pigment Red 73, and Pigment Red 83, Yellow pigments such asPigment Yellow 65, Pigment Yellow 82, Pigment Yellow 85, and Pigmentyellow 87, Blue pigments such as Pigment Blue 61, Pigment Blue 69,Pigment Blue 74, Pigment Blue 78, and Green pigments such as Green 70,also known as Pigment Green 7.

In one nonlimiting embodiment, the pigment additive is present in arange from about 0.01 to about 5 percent by weight.

In one nonlimiting embodiment, the polymer melt is produced by drying orpolymerizing via solid phase the first fiber forming polymer to adesired relative viscosity (RV) and feeding the dried or polymerizedfirst fiber forming polymer into extruder for remelting and spinning. Inembodiments comprising a pigment additive, pigment concentrates areadded through feeders at the throat of extruder at desired rates to makea given colored yarn. In one embodiment, the spin assist additive isadded, preferably as a pellet, at the extruder throat at the rate of0.5% to 5%. In another embodiment, the spin assist additive is extrudedin separate extruder and fed as melt stream into a transfer linecarrying molten base first fiber forming polymer. In this embodiment,mixing of spin assist additive in molten form is preferably accomplishedwith a twin screw extruder, and supplemented by suitable static mixersin the transfer line.

The synthetic fibers are then formed from the polymer melt. In onenonlimiting embodiment, the polymer melt is extruded through a spinneretto form one or a plurality of filaments. The one or a plurality offilaments are then drawn to form a synthetic fiber. In one nonlimitingembodiment, the fiber is drawn at a draw ratio of 2.65 or higher. In onenonlimiting embodiment, the number of broken filaments observed in a twominute interval while drawing the one or a plurality of filaments toform a synthetic fiber is less than 10. In another nonlimitingembodiment, the number of broken filaments observed in a two minuteinterval while drawing the one or a plurality of filaments to form asynthetic fiber is less than 5.

The method of the current invention can also be used to form polymermelts that can be extruded for other purposes. For example a polymermelt comprising a first polymer and an extrusion assist additive can beextruded in an additive printing machine (3D printing). Suitablepolymers include, but are not limited to nylon 6; nylon 6,6; nylon 4,6;nylon 6,12; nylon 6,10; nylon 6T; nylon 6I; nylon 9T; nylon DT; nylonDI; nylon D6; nylon 7; nylon 11; and nylon 12; and blends and copolymersthereof. Suitable extrusion assist additives include polyamidescomprising at least one aliphatic diamine and at least two distinctaromatic dicarboxylic acids, and copolymers and blends thereof. Examplesinclude, but are not limited to, polyamides comprising at least onealiphatic diamine selected from a group consisting of2-methyl-L5-pentamethylene diamine, hexamethylene diamine, 2-methylhexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethylhexamethylene diamine, 2,2-dimethylpentamethylene diamine,5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylenediamine and diaminodicyclohexyl methane and polyamides comprisingaromatic dicarboxylic acids are selected from a group consisting ofterephthalic acid, isophthalic acid and naphthalene dicarboxylic acidand 5-sulfoisophthalic acid. In one nonlimiting embodiment, theextrusion assist additive is selected from the group consisting of nylonDT/DI, nylon DT/6I, nylon DI/6T, nylon 6T/6I, nylon DT/DI/D6, nylon6T/6I/66 and copolymers and blends thereof.

Also provided by the present invention are synthetic fibers comprising afirst fiber forming polymer and a spin assist additive.

Examples of first fiber forming polymers used in these synthetic fibersof the present invention include, but are not limited to, polyamides,polyesters, polyolefins and combinations thereof. In one nonlimitingembodiment, the first fiber forming polymer is polyethyleneterephthalate. The polyamide may be selected from the list consisting ofnylon 6; nylon 6,6; nylon 4,6; nylon 6,12; nylon 6,10; nylon 6T; nylon6I; nylon 9T; nylon DT; nylon DI; nylon D6; nylon 7; nylon 11; and nylon12; and blends and copolymers thereof. In one nonlimiting embodiment,the first fiber forming polymer is nylon 6,6.

In one nonlimiting embodiment, the first fiber forming polymer ispresent in a range from about 75 to about 99 percent by weight.

Prior disclosed use for several of the polymers found by the inventorsherein to be useful as spin assist additives was for making injectionmolded articles, transparent nylon films, etc. Thus, efficacy of theseadditives as spin assist additives in the production of nylon fiber isunexpected. Spin assist additives used in the fibers of the presentinvention include polyamides comprising at least one aliphatic diamineand at least two distinct aromatic dicarboxylic acids, and copolymersand blends thereof. Examples include, but are not limited to, polyamidescomprising at least one aliphatic diamine selected from a groupconsisting of 2-methyl-L5-pentamethylene diamine, hexamethylene diamine,2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine,2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine,5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylenediamine and diaminodicyclohexyl methane and polyamides comprisingaromatic dicarboxylic acids are selected from a group consisting ofterephthalic acid, isophthalic acid and naphthalene dicarboxylic acid.In one nonlimiting embodiment, the spin assist additive is selected fromthe group consisting of nylon DT/DI, nylon DT/6I, nylon DI/6T and nylon6T/6I, and copolymers and blends thereof.

In one nonlimiting embodiment, the spin assist additive is nylon DT/DI,a composition comprising a copolyamide containing about 40 to about 80mol % 2-methyl-L5-pentamethyleneterephthalamide (“MPMD-T”) units andabout 20 to about 60 mol % 2-methyl-1,5-pentamethyleneisophthalamide(“MPMD-I”) units. In another nonlimiting embodiment, the copolyamide hasa relative viscosity (“RV”) of at least 1.90.

In one nonlimiting embodiment, the spin assist additive is present in arange from about 0.5 to about 5 percent by weight.

In one nonlimiting embodiment, the spin assist additive is present in arange from about 0.5 to about 20 percent by weight. In anothernonlimiting embodiment, the spin assist additive is present in a rangefrom about 0.5 to about 5 percent by weight.

In some embodiments of the synthetic fibers of the present invention, apigment additive is added. For purposes of the present invention, bypigment additive, it is meant to be inclusive, but is not limited to, acolor pigment of one of the three families of the trichromatic dye colorsystem (blues, yellows, reds) that can be added to a polymeric fiber inan amount effective to reduce the L* value of the fiber over a non-colorpigmented fiber. It is also meant to be inclusive of green pigments suchas Green 70 also known as Pigment Green 7. Preferable color pigments arestable in light (color fast). As those well versed in the art will note,the trichromatic color system is widely practiced in the fiber dyeingindustry. In this invention, the color pigments belong to this colorsystem of blues, reds and yellows. In one nonlimiting embodiment, thepigment additive is an organic pigment. Nonlimiting examples of pigmentadditives useful in the present invention include, red pigments such asPigment Red 60, Pigment Red 63, Pigment Red 80, Pigment Red 66, PigmentRed 67, Pigment Red 81, Pigment Red 68, Pigment Red 73, and Pigment Red83, Yellow pigments such as Pigment Yellow 65, Pigment Yellow 82,Pigment Yellow 85, and Pigment yellow 87, Blue pigments such as PigmentBlue 61, Pigment Blue 69, Pigment Blue 74, Pigment Blue 78, and Greenpigments such as Green 70 also known as Pigment Green 7.

In one nonlimiting embodiment, the pigment additive is present in arange from about 0.01 to about 5 percent by weight.

In addition, the present invention provides articles of manufacture, atleast a portion of which comprising a synthetic fiber of the presentinvention. Nonlimiting examples of articles of manufacture of thepresent invention include yarns formed from one or more of the syntheticfibers, carpet formed from these yarns, as well as fabric formed fromone or more these synthetic fiber.

Without being bound to any particular theory, it is believed that due todiminished nucleation and crystallinity, and improved clarity, the dyedand pigments articles, including yarns, fibers, filaments, and extrudedmicrofilaments, produced from compositions disclosed here will have abrighter, more attractive appearance. In white yarns, the process of thepresent invention are expected to yield deeper dyeing yarns (higher dyestrike rate). Further, using a spin assist additive in accordance withthe present invention is expected to improve yields and enable improvedproductivity in manufacturing thereby lowering costs.

The following section provides further illustration of the fabrics ofthis invention. These working examples are illustrative only and are notintended to limit the scope of the invention in any way.

EXAMPLES Example 1 Test Methods

Test methods used to evaluate the synthetic fibers and yarns produced inaccordance with the methods of the present invention included:

Draw ratio-to-break test: In this test, the draw ratio, which is theratio of chest roll speed to feed roll speed, is increased till thebreak of yarn is observed. That ratio-to-break is an indication of theeffectiveness of spin assist additive.

Draw tension test: Yarn draw tension is measured between the feed rolland the draw roll. In general, a lower draw tension indicates improvedspinnability.

The spinning performance was measured by broken filaments/2 minutes. Thenumber of broken filaments was observed by counting the number offlashes observed during the yarn spinning process. Each flash correlatedto a broken filament.

Example 2 1245 Denier BCF Pigmented Yarns Extrusion

A 1245 denier, 68 filament, 4-hole hollowfil, nylon 6,6 yarn was madeaccording to a process well known in the art. Nylon 6,6 copolymer flakewas conditioned to the desired RV, and fed into a twin screw extruderrunning at 190 rpm and a temperature profile of 230° C. at the feed and285° C. at the discharge. The melted polymer was passed through a heatedtransfer line, spinning pump and filter pack and then to a spinneretwhich formed the polymer into individual filaments. The total time thatthe mixture spent in the melt phase was approximately 8 minutes. Thefilaments were air quenched and then passed by a touch roller where asuitable finish was applied. The finished filaments were then convergedin a yarn bundle which was subsequently drawn, passed over heated rolls,bulk textured according the bulk texturing process described by Coon inU.S. Pat. No. 3,525,134, relaxed, and wound onto tubes. The nylon 6,6base copolymer was then conditioned to 195° C. and remelted using a twinscrew extruder. Control fiber (i.e. fiber spun without any additives),and additives nylon DT/6I, nylon DT/DI and nylon 6T/6I were premixedwith base nylon, and fed into the extruder. The pigment concentrates andadditives were fed through K-tron feeders and BCF yarn was spun usingstandard procedures.

Example 3 1245 Denier BCF Pigmented Yarns

A 1245 denier, 68 filament, 4-hole hollowfil, nylon 6,6 yarn was madeaccording to a process well known in the trade: nylon 6,6 flake was fedinto a twin screw extruder running at 190 rpm and a temperature profileof 230° C. at the feed and 285° C. at the discharge. The melted polymerwas passed through a heated transfer line, spinning pump and filter packand then to a spinneret which formed the polymer into individualfilaments. The total time that the mixture spent in the melt phase wasapproximately 8 minutes. The filaments were air quenched and then passedby a touch roller where a suitable finish was applied. The finishedfilaments were then converged in a yarn bundle which was subsequentlydrawn, passed over heated rolls, bulk textured according the bulktexturing process described by Coon in U.S. Pat. No. 3,525,134, relaxedand wound onto tubes.

The yarns spun are shown in Table 1.

TABLE 1 Draw Tension @ Loading Additive Feed Feed Roll DR = 2.65 yarnChest Roll Item Color ppm Additive rate, ppm DP Wrap (Front TL Only)needed Speed 2A Red 81- 4000 None NA 880 x 1250 1 doff 2425 25% 2B Red81- 4000 nylon 15,000 878 x 1250 1 doff 2425 25% DT/6I 2C Red 81- 4000nylon 30,000 790 x 1250 1 doff 2425 25% DT/6I 2D Red 81- 4000 nylon15,000 890 x 1250 1 doff 2425 25% DT/DI 2E Red 81- 4000 nylon 30,000 875x 1250 1 doff 2425 25% DT/DI 2F Red 81- 4000 nylon 15,000 875 x 1250 1doff 2425 25% 6T/6I 2G Red 81- 4000 nylon 30,000 880 x 1250 1 doff 242525% 6T/6I

Draw ratio-to-break tests were performed on these yarns. In these tests,the draw ratio (DR) was varied till the yarn broke. The higher the drawratio to break, the more robust is the yarn spinning. In addition, thenumber of flashes seen in hot chest roll over a 2 minute period wasrecorded for each draw ratio. The lower this number, the more robust isthe spinning process. This data is shown in Table 2.

TABLE 2 DR = 2.65 DR = 2.70 DR = 2.80 DR = 2.90 DR = 3.0 DR = 3.1 DR =3.2 Item Color BF BF BF BF BF BF BF 2A Red 81- 915 24 898 866 836 808782 758 25% 2B Red 81- 915 6 898 4 866 4 836 0 808 1 782 4 758 15 25% 2CRed 81- 915 2 898 7 866 1 836 0 808 4 782 2 758 3 25% 2D Red 81- 915 3898 2 866 6 836 2 808 0 782 4 758 2 25% 2E Red 81- 915 0 898 1 866 0 8360 808 0 782 0 758 0 25% 2F Red 81- 915 4 898 0 866 2 836 2 808 0 782 0758 1 25% 2G Red 81- 915 0 898 0 866 0 836 0 808 1 782 1 758 0 25% *BFrepresents the number of observed flashes in a 2 minute interval. Eachflash is understood to represent a broken filament.

The pigment additive used in these yarns was Red-81 which is difficultto spin. As shown in Table 2, control yarn without spin assist additivehad high broken filaments in 2 minutes even at a draw ratio of 2.65.Control yarn could not be spun at any higher draw ratio. However, whenusing spin assist additives nylon 6T/6I and nylon DT/DI, (see items 2D,2E, 2F and 2G), fibers could be spun without significant brokenfilaments even at draw ratios as high as 3.20. This indicates that thespin performance in a commercial machine would be much better uponaddition of spin assist additive agents in accordance with the presentinvention.

1. A process for forming a synthetic fiber, said process comprising thesteps of: (a) producing a polymer melt comprising a first fiber formingpolymer and a spin assist additive, wherein the spin assist additive ispresent in a range from about 0.5 to about 5 percent by weight; and (b)forming a synthetic fiber from the polymer melt.
 2. The process of claim1, wherein the spin assist additive is a polyamide comprising at leastone aliphatic diamine and at least two distinct aromatic dicarboxylicacids, and copolymers and blends thereof.
 3. The process of claim 2,wherein the at least one aliphatic diamine is selected from a groupconsisting of 2-methyl-1,5-pentamethylene diamine, hexamethylenediamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine,2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine,5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylenediamine and diaminodicyclohexyl methane.
 4. The process of claim 2,wherein the aromatic dicarboxylic acids are selected from a groupconsisting of terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid.
 5. The process of claim 2, wherein the spin assistadditive is selected from the group consisting of nylon DT/DI, nylonDT/6I, nylon DI/6T and nylon 6T/6I, and copolymers and blends thereof.6. (canceled)
 7. (canceled)
 8. The process of claim 1, wherein the firstfiber forming polymer is selected from the group consisting of apolyamide, polyester, polyolefin and combinations thereof.
 9. Theprocess of claim 8, wherein the first fiber forming polymer ispolyethylene terephthalate or nylon-6,6.
 10. (canceled)
 11. The processof claim 1 further comprising addition of a pigment additive to thepolymer melt, wherein the pigment additive is an organic or inorganicpigment and the pigment is present in a range from about 0.01 to about 5percent by weight.
 12. (canceled)
 13. (canceled)
 14. The process ofclaim 1, wherein forming a synthetic fiber comprises extruding saidpolymer melt through a spinneret to form one or a plurality offilaments, and drawing the one or a plurality of filaments to form asynthetic fiber.
 15. The process of claim 14, wherein the fiber can bedrawn at a draw ratio of 2.65 or higher.
 16. The process of claim 15,wherein the number of broken filaments observed in a two minute intervalwhile drawing the one or a plurality of filaments to form a syntheticfiber is less than
 10. 17. A synthetic fiber comprising: (a) a firstfiber forming polymer; and (b) a spin assist additive present in thesynthetic fiber at a range from about 0.5 to about 5 percent by weight,wherein the spin assist additive is a polyamide comprising at least onealiphatic diamine and at least two distinct aromatic dicarboxylic acids,and copolymers and blends thereof.
 18. (canceled)
 19. The syntheticfiber of claim 17, wherein the at least one aliphatic diamine isselected from a group consisting of 2-methyl-1,5-pentamethylene diamine,hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methylhexamethylene diamine, 2,5-dimethyl hexamethylene diamine,2,2-dimethylpentamethylene diamine, 5-methylnonane diamine,dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylenediamine, 2,2,7,7-tetramethyl octamethylene diamine anddiaminodicyclohexyl methane.
 20. The synthetic fiber of claim 17,wherein the aromatic dicarboxylic acids is selected from a groupconsisting of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and 5-sulfoisophthalic acid.
 21. The synthetic fiberof claim 17, wherein the spin assist additive is selected from the groupconsisting of DT/DI, DT/6I, DI/6T and 6T/6I, and copolymers and blendsthereof.
 22. (canceled)
 23. (canceled)
 24. The synthetic fiber of claim21, wherein the spin assist additive does not substantially copolymerizewith the first fiber forming polymer.
 25. The synthetic fiber of claim17, wherein the first fiber forming polymer is selected from the groupconsisting of a polyamide, polyester, polyolefin and combinationsthereof.
 26. The synthetic fiber of claim 25, wherein the first fiberforming polymer is selected from polyethylene terephthalate andnylon-6,6.
 27. (canceled)
 28. (canceled)
 29. (canceled)
 30. (canceled)31. An article of manufacture comprising the synthetic fiber of claim26.
 32. (canceled)
 33. (canceled)
 34. (canceled)